On the basis of many years of experience with failure events, Fraunhofer IWM has developed concepts for characterizing and analyzing failure in brittle materials such as glass and silicon. These concepts have been used many times on glass components for automotive applications, for architecture and in solar power modules and solar cells for determining the causes of failure. Tests are performed on single panes, domestic glass, solar wafers and solar cells and on complete units such as windows, complex glazing systems and solar modules that have been damaged or broken either during manufacture or later during use. These tests provide conclusions as to the mechanism of the breakage, the causes of failure, initial damage and how the failure developed. Identifying the causes of failure gives customers valuable insight into the development of manufacturing processes with low failure rates and into improving the mechanical properties of products during their end use.
Strength tests are performed after individual production steps in which the introduction of crack-like failures into the brittle material and the spread of pre-failure damage by each production step are quantified. Systematic investigations are performed to identify critical production steps. Knowledge about the critical production steps is important so that appropriate modifications to the production method can be made to improve the products and their reliability and durability.
In process analyses the effects of individual process steps on the production process are examined with regard to mechanical properties and strength. Depending on the specific application, such analyses contain experimental measurements e.g. of temperatures and tensions, plus investigations and tests at the production site and numerical simulations to display the stresses arising and to enable internal stresses and damage to be recorded. They provide our clients with sound data for the evaluation of production steps and for process optimization. Special test methods are also developed to allow early detection of pre-damaged parts and to allow items to be separated out during intermediate steps of the production process. The necessary qualitative criteria for classifying parts as ‘good’ or ‘bad’ are obtained from fracture mechanics analyses.
Fraunhofer IWM has decades of experience in investigating failure in brittle materials such as glass and silicon and we enjoy a close, trusting relationship with our clients. Our methodological approach to damage analysis results frequently in improvements, new developments, and increased product safety.